Culms densely tufted, ascending, lax or, occasionally, decumbent, 13-78 cm × 0.8-1 mm. Leaves: basal sheaths purple or purple tinged; sheaths 2-42 mm; blades ascending or lax, erect, green or yellow-green, midrib developed adaxially, 2 lateral veins abaxially, 19-38 cm × 1-5 mm, blades of overwintering leaves smooth. Inflorescences: peduncles proximal pistillate spikes to 11 cm, distal spike sessile; staminate spike 0.5-10.6 cm. Bracts 0.5-11.2 cm × 0.5-4 mm, angles of bract sheath denticulate; bract blade of distal lateral spikes linear, narrower than spikes, not concealing them; widest bract blade of distalmost lateral spike 0.5-3.4 mm wide. Spikes (3-)4(-5) per culm; lateral spikes 5-27 × 3-4 mm; internode between proximal scales in proximal spike 1.1-3.2(-4.8) mm; terminal spike linear, 11-21 × 1-2.2 mm. Pistillate scales 2.8-3 × 1-1.2 mm, apex acute to aristate, awn to 1 mm. Staminate scales 3.5-4 × 1.2-1.5 mm, margins hyaline, purple-brown or brownish purple tinged, apex acute. Anthers 2.6-3 mm. Perigynia 4-12 per spike, closely overlapping, aggregated, ascending, conspicuously (22-)25-32-veined, elliptic-obovate, 2.8-3 × 1.5-1.8 mm, 1.8-2.7 times long as wide; beak abruptly bent, 0.2-0.8 mm. Achenes obovoid, 2.6-2.8 × 1.3-1.6 mm. 2n = 33, 38, 40.
Fruiting spring. Moist to dry deciduous or mixed deciduous-evergreen forests or woodland edges in partial shade, frequently on limestone or chalk, on clay or marl soils, stream bottoms or on steep slopes; 0-600 m; Ont.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., Tenn., Tex., Va., W.Va., Wis.
Tufted, 2-8 dm, fertile stems mostly roughened on the angles; basal sheaths purple; lvs not glaucous, those of both fertile and sterile shoots 1-5 mm wide, or the latter larger, to 10 mm wide; angles of the bract-sheaths usually minutely ciliate-serrulate; terminal spike staminate, 0.6-2.5 cm, subsessile to evidently pedunculate; pistillate spikes 2-4, scattered but none basal, slender, 1-3 cm; pistillate scales cuspidate to short-awned; perigynia 4-18, only slightly overlapping (or the lowest scarcely so), 2.2-3 mm, finely many-nerved as well as 2-ribbed, obtusely trigonous, ellipsoid to obovoid, abruptly contracted to a short, abruptly bent beak with an entire orifice; achene trigonous; 2n=40. Sandy or rocky woods and open, sometimes disturbed sites, often calciphile; Que. and Vt. to Ga. and nw. Fla., w. to Wis., e. Nebr., and e. Okla. (C. laxiflora var. gracillima; C. ormostachya, largely northern, with the angles of the bract-sheaths merely granular)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.